/*
 * The MIT License (MIT)
 *
 * Copyright © 2020 xrv <xrg@live.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package io.github.ehlxr.rate;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 按比例控制流量
 *
 * @author ehlxr
 * @since 2019-07-19.
 */
public class RateBarrier {
    private final AtomicInteger op = new AtomicInteger(0);
    private List<Integer> source;
    private int base;
    private int rate;

    public boolean allow() {
        return source.get(op.incrementAndGet() % base) < rate;
    }

    private RateBarrier() {
    }

    public RateBarrier(int base, int rate) {
        this.base = base;
        this.rate = rate;

        source = new ArrayList<>(base);
        for (int i = 0; i < base; i++) {
            source.add(i);
        }

        // 打乱集合顺序
        Collections.shuffle(source);
    }

}
